2. Suppose we have three threads T1, T2 and T3 which perform sequentially one after another is their any benefit of using thread over here rather than having a single process?

here T1, T2 and T3 as a thread consumes less memory and
more speed

but as a process it consumes more memory.

Example:

Multiple threads can be run within a single memory
allocations.

but process needs seperate memory allocations for each
process.

3. What is the use of thread over process?

Thread is an executable entity but it is bound to its parent
process.
now there are two types of threads.
1. user space threads and
2. kernel thread
now the kernel threads are actually known as light weight
processes.

why light weight????
>>>> as it's context switching times is lesser than all
other process.

now why the context switching time is less????
>>>>> as process have there own process address space and
maintains many more things like userID, ProcessID, groupID,
number of files opened, reisters and blah, blah
whereas thread shares it's parent process's address space
and mainly contains three things like own stack, registers
and thread related data.
so more things to swap need more time that's why thread's
context switching time is less compared to that of a process.

now the answer,
use of thread: thread are used to provide multi-programming
environment.
ok, now u ppl would think that, it can also be done creating
new processes (using fork())
yes we can,
but as i told earlier that the context switch time for
threads are very less.
moreover the inter-thread communication is more easier than
inter-process communication as all threads of a single
process uses the same address space.

4. What is crondtab daemon?

The cron daemon reads the /etc/cronlog.conf configuration
file provided by the user to log the information. If a
configuration file has not been created, then the cron
daemon creates a log of its activities in the
/var/adm/cron/log file. The cron daemon reads the
configuration file when it is activated and when it receives
the hangup signal.

If the cron daemon is not able to create or open the
user-specified logfile, then it creates a log of its
activities in the /var/adm/cron/log file.

7. A _____Bios automatically assigns the necessary
configuration information (IRQs I/O addresses, and DMAS) to devices and avoid conflicts?

BIOS Has a set of routine to initialize the Bare hardware.
If "automatically assign" means initialization then the
proposition is right. Else... The BIOS inits the system
resources and stores the values in NVRAM(CMOS) the screen
you see for configuring the SYSTEM parameter is a depict of
CMOS/NVRAM not the BIOS.

When you configure the System, the post-BIOS routines read
those and prepares the system for start-up.

9. A _____ cpu is a cpu that has a speed greater than the speed that was originally intended for the processor?

its called overclocking, generally the processor is set to
a low clock rate which can be increased to higher clock
frequencies. Example a P4 3Ghz processor could be
overclocked to 4.2 Ghz but it requires a lot of skills and
additional heat sinks to dissipate the energy. Also, it can
lead to permanent damage of processor

10. What is the scope and packages being offered after the Linux course completion?

You will concentrate on shell scripting and database like
Oracle, Sql etc., The Redhat offer RHSA, RHSS courses

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11. What are different ways of creating threads?

In a process at least one thread will always be there.
So i think, when we create a new process using fork() system, this is also a thread creation (single thread only).

12. What is LD_LIBRARY_PATH?

This is one system administrator's point of view why
LD_LIBRARY_PATH, as frequently used, is bad. This is written
from a SunOS 4.x/5.x (and to some extent Linux) point of
view, but this also applies to most other UNIXes.

LD_LIBRARY_PATH is an environment variable you set to give
the run-time shared library loader (ld.so) an extra set of
directories to look for when searching for shared libraries.
Multiple directories can be listed, separated with a colon
(:). This list is prepended to the existing list of
compiled-in loader paths for a given executable, and any
system default loader paths.

For security reasons, LD_LIBRARY_PATH is ignored at runtime
for executables that have their setuid or setgid bit set.
This severely limits the usefulness of LD_LIBRARY_PATH.

13. How to recover the linux system after it was crashed?

boot the system through 1st CD and after give time and all
setting then on installing SCREEN type 'rescue' for go to
rescue mode, then type #mount /chroot/sysimage then enter
know what ever problem u have u can trableshoot either
filesystem or grub if it is related to grub then type
'#fdisk -l' to see the partition type then install grub by
'grub-install /dev/hda,b,c' or what ever ........